Cap for tire-valve tubes



M. M. METZINGER CAP FOR TIRE VALVE TUBES April 16, 1929.

Filed Oct. 1927 II I Ill Y MYF-ON M.Mn'rzmaz.x.. amvmdo'n attorney Patented Apr. 16,1929.

warren stares new MYRON M. rvrn'rzmena, or BLAIfi, rtnnaasxa;

cannon TIRE-VALVE 'rnnns.

Application filed October v3, 1927. S.eria1-1 T0. 223,7S5.

My invention relates to caps for the valvetubes of pneumatic tires, and it is the general object thereof to provide a'simple, efficient and inexpensive device of this kind, adapted to hold or retain air-pressure within the 13116 regardless of leakage throughthe valve itself. A more particular object of my lnvention is to provide a tire valve tube cap having a seat or gasket of soft metal instead of rubber or other non-metallic packing material, to provide means for retaining the metal seat or gasket within the cap, and to provide means for preventing destructive deformation of thesoft metal seat or. gasket by the pressure of the tube-end thereon.

In the accompanying drawings Fig. 1 1s a longitudinal section ofa partially completed cap embodying my invention, Fig. 2 1s a similar view of the completed cap, Fig. 3 1s a longitudinal section of the cap as screwed partly onto the valve-tube, Fig. 4 is a similar view showing the cap fully seated upon the tube, Fig. 5 is a bottom view of the cap, Fig. 6 is a side view of the same, and Fig. 1s a plan view thereof.

In carrying out my invention I preferably form the cap from a piece of hexagonal rod which is cut to a suitable length for the body 11, the closed end being slightly rounded at the edges 12, and the other end being formed witha short conical countersink 13 extending to the threaded bore 14. At the innerend of the threaded bore 14 there is formed an annular groove 15 which originally is rectangular in section as shown in Fig. 1, and has an outer diameter slightly less than the root diameter of the threads 14. At the center of the closed end of the cap is drilled a hole 16,

slightly greater in depth than the groove 15. and between said hole and groove there is an annular flange 17.. Within the groove 15 is disposed a ring 18 of soft'metal, such as lead, the thickness of said'ring being slightly less than the depth of the groove, sothat the flange 17 extends slightly beyond the end of the ring at the open end of the groove, as

shown in Fig. 1. After the soft metal ringv V 2. The soft metal ring is thus firmly (not shown) secured in the annular groove at the end of the cap, and is also compressed or consolidated by the swaging pressure exerted thereon by the expanding of the flange, whereby any sponginess or lack of solidity of the soft metal will be obviated.

In the ordinary standard valve-tube, co1n monly provided for pneumatic tires, the end portionof the tube 20 is threadedexternally to receive the cap, and is threaded internally to receive the removable valve structure, the

end of the tube intermediate'the roots of the external and internal threads being rounded to an, annular ridge 21, as best shown in Fig.

3. The threadedbore 1403f my improved] cap is adapted to screw onto the external threads of the tube 20 in the usual manner,

and the outer diameter of the lip 19 is such that said lip may pass inside the ridge 21 at the end of the valve-tube,.although with very slight clearance between them. Thus when 18 and becomesbedded'into said surface as shown in Fig. 4, to form a substantially ,per- 7 feet air-tight joint capable of resisting great air-pressure without leakage. Undue fdeformation or displacement of the soft metal from the groove 15 is prevented by. the confinement thereof at all sides, except-at the slight clearance-space between the lip 19 and the inner edge of the ridge 21, and this spaceis too narrow to allow any appreciable extrusion of the soft metal by the-pressure result ng from screwing down the cap sufficiently tov retain the air. The surface ofthe soft metal engaged by the ridge 21 becomes burnished or polished by its contact with the f ridge, and the wear of the contacting surfaces, by repeated removal and replacement of the cap, is so small as to be negligible.

valve tube 20.

1. A valve-tube cap comprising a body- The hole 16 within the annular flange 17 provides for the usual projection of the valve-stem to a pomtbeyond, the end of the I member having a threaded portionfor en s" gaging the screw threads of a valve-tube, and havlng an annular groove acqommg the end of said threaded portion, asoft metal ring disposed in saidgroove, and an annular lip integral with the body-member and extending 7 sure of the end of the Valve-tube thereon.

' 2. A valve-tube cap comprising a cup- V shaped member internally threadedto engage the screw-threads of a valve-tube,'andl1aving Within the closedend thereof an integral annular flange, there being a central recess inside and an annular groove outside said annular flange, and a soft metal ring disposed in said annular groove and retained therein by expansion of theend portion of the annular flange partially thereover the exposed surface of the softmetal' ring being adapted for engagement with the end of the valve-tube When the cap is screwed thereon.

MYR-ON M. METZINGER'. 

